Why is it difficult to create a vaccine against cholera

A vaccine against cholera has already been created. It was first made during the 1800's. Even so, it's limited supply for places such has Haiti.

Spanish physician Jaume Ferran i Clua developed a cholera inoculation in 1885, the first to immunize humans against a bacterial disease. Russian-Jewish bacteriologist Waldemar Haffkine developed the first cholera vaccine in July 1892. It is already discovered

answer: the answer is b

not necessarily. higher fitness requires the organism to be reproductive successful. for example, an organism at age 10 with 15 offspring is much more fit than an organism at age 15 with only 5 offspring.